1. Field of the Invention
The present invention relates to a hand-held telephone set and particularly to a hand-held telephone set to which a plurality of telephone numbers can be assigned.
2. Description of the Related Art
With rapid popularization of hand-held telephone sets in these years, there has been a need for assigning two or more telephone numbers to a hand-held telephone set. For example, two different telephone numbers are assigned to a hand-held telephone set and this hand-held telephone set can selectively be put into personal use and business use by selecting the telephone numbers for actual use. Therefore, the telephone rate can be clearly distinguished for business use and personal use. In general, the assigned telephone numbers can be selectively changed in this hand-held telephone set by user's manual manipulation.
However, when two telephone numbers are selected depending only on user's will, it is possible, for example, to make a personal conversation using the telephone number assigned for business use and the telephone rate may be charged to a company. Moreover, it is also conceivable that a conversation, although it is a business conversation, is attempted using the telephone number assigned for personal use and its telephone rate is charged to a person.
As explained above, the requirement for which a user is requested to change over the telephone numbers for the business use and personal use will easily generate various disadvantages. Therefore, it is required to automatically change over the telephone numbers.
A system of automatic changeover of the telephone number is described in the Japanese Patent Laid-Open No. HEI 1-300723. The related art described in this reference is devised not to pay expensive roaming charge by previously storing regional numbers corresponding to different telephone numbers within the telephone set and receiving a signal from a base station of the region to which the telephone set is moved in order to automatically select the most appropriate telephone number of the relevant region as the telephone number of the telephone set.
However, the related art described in this reference cannot be used for changeover of the telephone numbers for business use and personal use because the telephone number is only changed over to that corresponding to the region to which the telephone set is moved. Namely, in this related art, the telephone numbers for business use and personal use cannot be used in the same region and thereby the related art cannot be applied for actual use.
For this reason., it has been considered to limit to the telephone set so that when the telephone number is changed over to the number for business use depending on the company's will, a call can be originated only to the specified parties. However, this limitation may result in the fear that an expectedly large telephone rate is charged on a company when the telephone set is used in the remote area. Moreover, since there is no limitation on the incoming calls, the telephone rate on the basis of cash on delivery, for example, will be charged on a company.